July 22, 2009

The Master Zombie Argument

Berkeley's so-called 'Master Argument' and Chalmers' 'Zombie Argument' are two famous arguments that turn on the relationship between conceivability and possibility. I have been thinking for some time about an amusing (and perhaps somewhat troubling) way of putting the two together. First, let me give simplified versions of the two arguments.

The Master Argument (MA):

(MA1) Whatever is conceived is conceived by some mind.

(MA2) Whatever is conceived by a mind is in that mind.

Therefore,

(MA3) Nothing can be conceived that is not in a mind.

(MA4) Whatever is inconceivable is impossible.

Therefore,

(MA5) It is impossible for anything not to be in a mind.

The Zombie Argument (ZA):

(ZA1) It is conceivable that all the physical facts should be the same but the phenomenal facts (i.e. facts about conscious experiences) should be different (or altogether lacking).

(ZA2) Whatever is conceivable is possible.

Therefore,

(ZA3) It is possible that all the physical facts should be the same but the phenomenal facts should be different (or altogether lacking).

(ZA4) If it is possible for a set of facts S1 to be held constant while another set of facts S2 is changed, then S1 does not adequately explain S2.

Therefore,

(ZA5) The physical facts do not adequately explain the phenomenal facts.

These are just rough, simplified sketches off the top of my head, not serious interpretations of either Berkeley or Chalmers. Both arguments admit of more sophisticated versions. (In fact, there had better be a more sophisticated version of (MA): as it is, it seems to require that even minds themselves be in minds.) Now, consider the following bizarre merger of the two:

The Master Zombie Argument (MZA):

(MZA1) Any phenomenal property that is conceived is conceived by some mind.

(MA2) Whatever is conceived by a mind is in that mind.

Therefore,

(MZA2) No mind M can conceive any phenomenal property that is not in M.

(MA4) Whatever is inconceivable is impossible.

Therefore,

(MZA3) No phenomenal property can exist outside M.

Therefore,

(MZA4) There is only one entity having phenomenal properties, namely, M. (Either solipsism or pantheism is true.)

What should be said about (MZA)? Well, there seems to be some kind of a "conceivable by whom?" problem. Couldn't there be some other mind, M2, such that M can conceive of all and only M's possible phenomenal properties and M2 can conceive of all and only M2's possible phenomenal properties (where the two sets of possible phenomenal properties are disjoint)? Perhaps, but there are two problems with this approach. The first problem is that we ordinarily think of ourselves as being able to conceive of the phenomenal properties of other human beings (we think they are similar to our own), so (MZA) will still lead to one of two odd conclusions: either (a) we cannot conceive of the phenomenal properties of other human beings, or (b) the phenomenal properties ordinarily attributed to various (supposedly) distinct human beings actually inhere in a single substance. The second problem is that M could not possibly have good reason to believe that M2 has phenomenal properties, since those properties are not conceivable by M. As a result, M cannot have good reason to think that anything is conceivable by M2 (or any other mind), so M should suppose that whatever is inconceivable by it is inconceivable absolutely.

Good thing (MA4) is false.

Posted by Kenny at July 22, 2009 12:11 PM

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Comments

The problem with the Master Argument comes long before MA4. It conflates actual properties with conceived properties in the same kind of way as found in the ontological argument. Santa is conceived to be flesh and blood, but actually is a mere figment of our imaginations. Likewise, we can conceive of a tree being unperceived, even though we actually have an image of it in mind. So just because anything conceived is, in some sense, "in mind", it doesn't follow that such mentality is part of the content being conceived of; and of course it is the content that's relevant for possibility-conceivability inferences.

But Berkeley believes that ideas properly so-called (as opposed to notions) are not ideas 'of' anything. There is not a confusion between ideas and their objects because, according to Berkeley, ideas don't have objects (or, as some commentators prefer to say, ideas are their own objects).

This means that, at best, the argument (in my bad schematization of it) relies on controversial premises. At worst, it might be thought downright question-begging; after all, if you already believe (MA2) - that whatever is conceived is genuinely in the mind that it is conceived by, in the strong sense needed by the argument - then you are effectively already an idealist.